The present invention relates to a self-tightening keyless chuck to enable electric percussive drills to grip a tool shank. The chuck includes a rear sleeve, a body, a bearing ring, a bearing assembly, a nut, a jaw, a front sleeve and a stopper and so on. The bearing assembly utilizing a ball bearing is positioned with a circumferential arcuate race with a fixed depth, and the bottom surfaces of said circumferential arcuate race are provided with a plurality of ball-shape grooves. During the chuck grips a tool shank, the balls of said ball-bearing enter into the ball-shape grooves and are locked there, so as to prevent the tool from loosening due to the percussion vibration. In addition, the front sleeve engages with a nut through radial smooth press-fit to securely transmit a torque.
|
1. A self-tightening keyless chuck for gripping a tool shank, comprising:
a rear sleeve (1);
a body (2);
a bearing ring (3);
a bearing assembly (4);
a nut (5);
a jaw (6);
a front sleeve (7); and
a stopper (8),
wherein a surface of at least one of the bearing ring (3) and the nut (5) that faces the bearing assembly (4) is provided with a recessed circumferential arcuate race (9), and a plurality of ball-shape grooves (10) are uniformly formed in an arcuate bottom surface of the arcuate race (9), and
wherein the front sleeve (7) engages with the nut (5) through radial smooth press-fit.
3. A self-tightening keyless chuck for gripping a tool shank, comprising:
a rear sleeve (1);
a body (2);
an upper bearing ring (31);
a bearing assembly (4);
a lower bearing ring (32);
a nut (5);
a jaw (6);
a front sleeve (7); and
a stopper (8),
wherein a surface of at least one of the upper bearing ring (31) and the lower bearing ring (32) that faces the bearing assembly (4) is provided with a recessed circumferential arcuate race (9), and a plurality of ball-shape grooves (10) are uniformly formed in an arcuate bottom surface of the arcuate race (9), and
wherein the front sleeve (7) engages with the nut (5) through radial smooth press-fit.
2. The self-tightening keyless chuck according to
4. The self-tightening keyless chuck according to
and wherein two parallel cut-out surfaces (13) are symmetrically formed on an outer peripheral surface of the nut (5), which extend downwards in an axial direction from a front end surface of the nut (5) by one third of a thickness of the nut and are located at an angle of 90° relative to the positions of angularly-cut split notches (11).
5. The self-tightening keyless chuck according to
6. The self-tightening keyless chuck according to
7. The self-tightening keyless chuck according to
8. The self-tightening keyless chuck according to
|
The present application relates to a keyless chuck and, more particularly, to a self-tightening keyless chuck. Generally, an electric percussive drill is capable of reciprocating, percussive vibration as well as rotary motion. Therefore, the present invention particularly provides a self-tightening keyless chuck for maintaining a secure grip on such a tool in percussive motion.
A variety of keyless chucks have been developed so far. A conventional chuck generally comprises a rear sleeve, a body, a bearing ring, a bearing, a nut, a jaw, a front sleeve, a stopper and so one. The jaw extends/retracts under the rotation of the nut and the engagement of conical threads, and the nut is rotated by movement of the front sleeve. Such a chuck is keyless if the front sleeve is rotated by hand. The chuck may be attached to a driving shaft of a drill by means of threads or a conical bore.
A conventional keyed or keyless chuck has the disadvantage that because the nut and the jaw are secured only by rotation of threads, the jaw tends to loosen its grip on a tool due to axial percussive vibrations transmitted through the chuck and the tool during operation. This will cause the tool to skid, thus resulting in a loss of working efficiency and a loss of safety.
A conventional chuck is disclosed in Chinese Patent Publication CN1068532 (Chinese Patent Number: ZL 92104999.4), in which the anti-percussion of the chuck is achieved by forming spokewise grooves in the surfaces of two members that act as bearing races, the opposing sides of the grooves being provided with round angles of different radii. The depth of the grooves has a great influence on the anti-percussion ability of the chuck as well as on the release of the chuck. If the grooves are too deep, the chuck will not be released after use. If the grooves are too shallow, the chuck will have a poor anti-percussion performance. Therefore, in order to keep a uniform depth of the grooves in all members to thereby ensure the anti-percussion ability of all chucks, it is necessary to frequently adjust the machine for manufacturing the members. This, however, will affect the efficiency of production and can result in an increase of defective products. To overcome this drawback, it is necessary to provide a pressing machine with a higher pressing accuracy or larger tonnage, which however will increase the cost of production.
Furthermore, the front sleeve of a conventional keyless chuck is generally made of plastic. The chuck generally has a configuration in which a steel ring is embedded in an inner side of the plastic front sleeve, and two nut halves that are placed in a circular groove in the body of the chuck are press-fit into the hole of the steel ring embedded in the inner side of the plastic front sleeve, thereby securing the two nut halves in the circular groove in the body. This configuration, however, is complicated in structure and manufacturing process, and the front sleeve of the chuck which has a low strength is susceptible in damage.
To overcome the aforementioned disadvantages and drawbacks in the prior art, the present invention provides a safe and simple self-tightening keyless chuck, which has a locking function and improves the strength of a front sleeve and which is less susceptible to loosening when used for a percussive tool.
In order to fulfill the above object, the present invention employs the following technical solution.
The invention provides a self-tightening keyless chuck for gripping a tool shank, comprising a rear sleeve, a body, a bearing ring, a bearing assembly, a nut, a jaw, a front sleeve and a stopper, wherein the surface of at least one of the bearing ring and the nut that faces the bearing assembly is provided with a recessed circumferential arcuate race, and a plurality of ball-shape grooves are uniformly formed in an arcuate bottom surface of the arcuate race, and wherein the front sleeve engages with the nut through radial smooth press-fit.
The nut is provided with two angularly-cut split notches that are symmetrically positioned on both ends of a diameter of the nut, the angularly-cut split notches having a cut-out angle between 30 and 75°.
Alternatively, the invention provides a self-tightening keyless chuck for gripping a tool shank, comprising: a rear sleeve, a body, an upper bearing ring, a bearing assembly, a lower hearing ring, a nut, a jaw, a front sleeve and a stopper, wherein the surface of at least one of the upper and lower bearing rings that faces the bearing assembly is provided with a recessed circumferential arcuate race, and a plurality of ball-shape grooves are uniformly formed in the arcuate bottom surface of the arcuate race, and wherein the front sleeve engages with the nut through radial smooth press-fit.
In this self-tightening keyless chuck, the nut is provided with two angularly-cut split notches that are symmetrically positioned on both ends of a diameter of the nut, the angularly-cut split notches having a cut-out angle between 30 and 75°. Further, two parallel cut-out surfaces are symmetrically formed on the outer peripheral surface of the nut, which extend downwards in an axial direction from the front end surface of the nut by one third of the thickness of the nut and are located at an angle of 90° relative to the positions of angularly-cut split notches.
The front sleeve is press cast using a press-casting metal or a powdered metallurgic material.
In the above two self-tightening keyless chucks, the recessed circumferential arcuate race has an arc radius R of from 1.5 to 2.5 millimeters.
The recessed circumferential arcuate race has a depth 11 from 0.05 to 0.30 millimeters.
The number of ball-shaped grooves ranges from 20 to 80.
The ball-shaped grooves have a spherical radius r from 1.0 to 2.0 millimeters.
The ball-shaped grooves have a depth h from 0.01 to 0.10 millimeters.
In the alternative self-tightening keyless chucks for gripping a tool shank, the upper bearing ring and the lower bearing ring may have the same external dimensions and the same surface structure.
The upper bearing ring and the lower bearing ring may also have different external dimensions and different surface structures, and their differences include the inside diameter and the thickness of the bearing rings.
During operation, the balls of the bearing assembly enter the ball-shaped grooves of the bearing ring or the nut and are locked therein. Alternatively, the balls of the bearing assembly enter the ball-shaped grooves of the upper bearing ring or the lower bearing ring and are locked therein. Thus, the nut is less susceptible to loosening in operation, so that the chuck maintains a great gripping force.
The present invention has an advantage that the depth of the ball-shaped grooves which is essential to the anti-percussion ability of the chuck is determined by a mould. That is, the optimum distance (i.e., depth of the ball-shaped grooves) between the ball-shaped grooves and the arcuate bottom surface of the recessed circumferential arcuate race has been determined during the manufacturing of the mould. In this way, the pressing of the members has nothing to do with the adjustment or accuracy of the machine for manufacturing the members, whereby the depth of the ball-shaped grooves in all members can be constantly maintained within an optimum range to ensure the anti-percussion performance of all chucks.
The present invention has another advantage that due to the use of the recessed arcuate race, the balls of the bearing assembly are constantly constrained within the arcuate race. This will ensure the centering of the members under force, so that the three jaws of the chuck are subjected to a uniform force to thereby increase the gripping force.
The present invention has still another advantage that because the front sleeve is press cast using a press-casting metal or a powdered metallurgic material, the front sleeve has an increased strength and can be directly engaged with the nut through press-fit to securely transmit a torque.
By using the above configurations, the present invention overcomes the problem that a conventional chuck either does not have a locking means or has a locking means with unsatisfactory performance. The chuck according to the present invention can be operated in a quick, reliable, safe and convenient way. It provides such advantages as a reasonable structure, a convenient assembly, a stable performance and a reliable operation. The present invention can be used in all kinds of keyed or keyless chucks.
A detailed description of the present invention is provided with reference to the drawings and embodiments below.
Referring to
During assembly, the metal front sleeve 7 engages, through press-fit, with the nut 5 that is placed in a circular groove in the body 2 and split into two halves by split notches 11. Thanks to the strength and the elastic/plastic deformability of the metal material per se, the metal front sleeve 7 is securely connected to the nut 5 through press-fit, thus ensuring transmission of an input torque. Before press-fit, the metal sleeve 7 is surface-treated by electrophoresis painting, static plastic spraying or anodized processing so that its surface meets different requirements in color.
Tian, Xianming, Pei, Huijun, Su, Lihang, Xu, Qiaoyu
Patent | Priority | Assignee | Title |
Patent | Priority | Assignee | Title |
2910302, | |||
4305597, | Nov 19 1979 | Black & Decker Inc. | Keyless self-tightening chuck |
5044643, | Jun 16 1989 | Kabushiki Kaisha Delta | Tool chuck |
5145194, | Jun 21 1991 | JACOBS CHUCK MANUFACTURING COMPANY, THE | Impact tool chuck |
5174588, | Feb 23 1990 | Robert Bosch GmbH | Automatically locking chuck for drill or the like |
5215317, | May 18 1992 | JACOBS CHUCK MANUFACTURING COMPANY, THE | Keyless chuck |
5411275, | Sep 27 1993 | JACOBS CHUCK MANUFACTURING COMPANY, THE | Chuck with torque limiting mechanism and inclined plane for final tightening |
5476273, | Dec 11 1989 | JACOBS CHUCK MANUFACTURING COMPANY, THE | Plastic grip boots for chucks |
5531461, | Sep 27 1993 | JACOBS CHUCK MANUFACTURING COMPANY, THE | Chuck with torque limiting mechanism and inclined plane for final tightening |
5669616, | Nov 13 1995 | CHUM POWER MACHINERY CORPORATION | Tool chuck |
5934689, | Feb 17 1998 | JACOBS CHUCK MANUFACTURING COMPANY, THE | Chuck having sleeve retaining nut |
5944328, | Feb 20 1998 | Chum Power Machinery Corp. | Chuck |
6010135, | May 29 1997 | JACOBS CHUCK MANUFACTURING COMPANY, THE | Chuck |
6217033, | Aug 13 1998 | Yokiwa Seiko Kabushiki Kaisha | Chuck device |
6260856, | Nov 17 1999 | JACOBS CHUCK MANUFACTURING COMPANY, THE | Locking chuck |
6991238, | Jul 15 2003 | Shandong Weida Machinery Co., Ltd.; SHANDONG WEIDA MACHINERY CO , LTD | Locking drill chuck |
7040630, | May 12 2000 | Insty Bit Acquisition, LLC | Chuck with quick change |
20020180164, | |||
CN2233298, | |||
CN2235871, |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Aug 09 2002 | Shanxi Huifeng Power Tools Co., Ltd. | (assignment on the face of the patent) | / | |||
Sep 09 2004 | TIAN, XIANMING | SHANXI HUIFENG POWER TOOLS CO , LTD | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 016804 | /0671 | |
Sep 09 2004 | PEI, HUIJUN | SHANXI HUIFENG POWER TOOLS CO , LTD | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 016804 | /0671 | |
Sep 09 2004 | SU, LIHANG | SHANXI HUIFENG POWER TOOLS CO , LTD | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 016804 | /0671 | |
Sep 09 2004 | XU, QIAOYU | SHANXI HUIFENG POWER TOOLS CO , LTD | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 016804 | /0671 |
Date | Maintenance Fee Events |
Feb 28 2011 | REM: Maintenance Fee Reminder Mailed. |
Jun 25 2011 | M2551: Payment of Maintenance Fee, 4th Yr, Small Entity. |
Jun 25 2011 | M2554: Surcharge for late Payment, Small Entity. |
Mar 06 2015 | REM: Maintenance Fee Reminder Mailed. |
Jul 24 2015 | EXP: Patent Expired for Failure to Pay Maintenance Fees. |
Date | Maintenance Schedule |
Jul 24 2010 | 4 years fee payment window open |
Jan 24 2011 | 6 months grace period start (w surcharge) |
Jul 24 2011 | patent expiry (for year 4) |
Jul 24 2013 | 2 years to revive unintentionally abandoned end. (for year 4) |
Jul 24 2014 | 8 years fee payment window open |
Jan 24 2015 | 6 months grace period start (w surcharge) |
Jul 24 2015 | patent expiry (for year 8) |
Jul 24 2017 | 2 years to revive unintentionally abandoned end. (for year 8) |
Jul 24 2018 | 12 years fee payment window open |
Jan 24 2019 | 6 months grace period start (w surcharge) |
Jul 24 2019 | patent expiry (for year 12) |
Jul 24 2021 | 2 years to revive unintentionally abandoned end. (for year 12) |